Ammonia → 4-Chloro-1-(piperidin-4-yl)-1,3-dihydro-2H-benzimidazol-2-one

Participants

Reaction Steps

tert-butyl 4-(4-chloro-2-oxo-2,3-dihydro-1H-benzimidazol-1-yl)piperidine-1-carboxylate from Step B (2.17 g, <6.17 mmol) was dissolved in dichloromethane (10 mL) and trifluoacetic acid (5 mL) was added at room temperature. After 5 h, additional trifluoacetic acid (5 mL) was added and the reaction stirred overnight. To this solution was added 2.0 M ammonia in methanol, the mixture was filtered and the volatiles removed in vacuo. The crude product was purified by chromatography (silica gel, 1 to 25% methanol containing 1% NH3 in methylene chloride gradient elution), which gave the title compound (1.12 g). MS 352.2 (M+1).

Provenance & Evidence